 /*******************************************************************************
  * Copyright (c) 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  ******************************************************************************/

 package org.eclipse.ui;

 import java.util.Map ;

 /**
  * <p>
  * A listener to changes in a particular source of information. This listener is
  * notified as the source changes. Typically, workbench services will implement
  * this interface, and register themselves as listeners to the
  * <code>ISourceProvider</code> instances that are registered with them.
  * </p>
  *
  * @since 3.1
  * @see org.eclipse.ui.ISources
  * @see org.eclipse.ui.ISourceProvider
  */
 public interface ISourceProviderListener {

     /**
      * Handles a change to multiple sources. The source priority should be a bit
      * mask indicating the sources. The map will be used to construct the
      * variables on an <code>IEvaluationContext</code>
      *
      * @param sourcePriority
      * A bit mask of all the source priorities that have changed.
      * @param sourceValuesByName
      * A mapping of the source names (<code>String</code>) to the
      * source values (<code>Object</code>). The names should
      * never be <code>null</code>, but the values may be. The map
      * must not be <code>null</code>, and should contain at least
      * two elements (one for each source).
      * @see org.eclipse.core.expressions.IEvaluationContext
      * @see ISources
      */
     public void sourceChanged(final int sourcePriority,
             final Map sourceValuesByName);

     /**
      * Handles a change to one source. The source priority should indicate the
      * source, and the name-value pair will be used to create an
      * <code>IEvaluationContext</code> with a single variable.
      *
      * @param sourcePriority
      * A bit mask of all the source priorities that have changed.
      * @param sourceName
      * The name of the source that changed; must not be
      * <code>null</code>.
      * @param sourceValue
      * The new value for that source; may be <code>null</code>.
      * @see org.eclipse.core.expressions.IEvaluationContext
      * @see ISources
      */
     public void sourceChanged(final int sourcePriority,
             final String sourceName, final Object sourceValue);
 }

